Catalytic conversion of hydrocarbon oils



May 12, I942. ca. EGLOFF 2,282,855

CATALYTIC CONVERSION OF HYDROGARBON OILS Filed June 29,1940

RECEIVER ONDENSER all JVEATER FRACTION/17701? SEPAFA TIACG C-IIAMBERREACTION CHAMBER Patented May 12, 1942 CATALYTIC CONVERSION OF HYDRO-OARBON OILS Gustav Eglotf, Chicago, Ill., assignor to Universal OilProducts Company, Chicago, Ill., a corporation of Delaware ApplicationJune 29, 1940, Serial No. 343,198

5 Claims.

The invention is particularly concerned with an improved process for thecatalytic cracking of hydrocarbon oils.

The process-is of the general type in which a catalytically active solidmaterial, capable of promoting the cracking reaction and in finelydivided or powdered form, is dispersed within the oil to be cracked andthe dispersion passed through a heating coil and succeeding reactionzone wherein the catalytic cracking reaction takes place, the resultingproducts passing from the reaction zone to subsequentresidue separating,fractionating, condensing and collecting steps and the process beingoperated for the production of high yields of good antiknock gasoline.

In the improved process of the present invention, provision is made forestablishing a cyclic flow of conversion products and catalyst'throughthe reaction zone. This is accomplished by removing the mixture ofconversion products and catalyst from the outlet end of the reactionzone, supplying a portion of this mixture to the subsequent residueseparating step and continuously returning another portion thereof to oradjacent the inlet end of the reaction zone.

in the temperature which would otherwise normally prevail in thereactilm zone.

The-improved yields and octane number of the gasoline produced, whichmay be obtained by employing the features of the invention, may be due,in part, to some beneficial reaction between the hot recycled gases andother reactants or conversion products present in the reaction zone Thisimprovement results in more complete utilization of the catalyst which,I have found,

still retains considerable catalytic activity after it has passed onceor several times through the reaction zone. Also, due to the recyclingof regulated quantities of the catalyst-containing conversion products,I am able to employ a smaller reaction zone for the same degree ofconversion as would be obtained with a correspondingly larger reactionzone wherein the heated hydro carbons and catalyst from the coil arepassed only once therethrough or, with a reaction zone ofequal size, Iam able to obtain a higher degree ture in the reaction zone withoutexternal heating thereof and is particularly advantageous in combinationwith the cyclic flow of catalyst containing conversion products throughthe reaction zone, since the latter, without the last named feature,would result in aconsiderable reduction and/or to polymerization oralkylation or both of components of the recirculated gas stream in thereaction zone, since the normally gaseous products produced in this typeof catalytic cracking operation normally contain substantial quan titlesof relatively high-boiling olefins as well as corresponding paraflines.However, I do not offer this as a conclusive or complete explanation ofthe beneficial results obtained-by employing the improvements providedby the invention, since the various conversion reactions which will takeplace in such a system are difllcult to predict or identify.

The accompanying drawing diagrammatically illustrates one specific formof apparatus embodying the features of the invention and in which theimproved process may be conducted.

Referring to the drawing, the charging oil,

which will beany oil amenable to catalytic cracking and in which thedesired quantity of powdered catalyst has been suspended or thoroughlydispersed by any well known means, not illustrated, is supplied throughline I and valve 2 to pump 3 and is fed therefrom through line 4 andvalve 5 to heating coil 6 disposed in furnace l. The oil and catalystare heated in passing through coil 8 to .a temperature at which thedesired catalytic cracking reaction will take place and the heatedmaterial is directed from coil 6 through line 8 and valve 9 intoreaction zone Ill.

The reaction zone, in the particular case here illustrated, comprises avertically disposed enlarged reaction chamber, to the upper portionportion of chamber In is directed through line l2 and valve I3 toseparating chamber H and the remainder is supplied through valve 15 inline H to pump l6 which may. for example, be a centrifugal pump capableof keeping the catalyst particles in suspension or disrersion in theconversion products and whereirom Mi stream of conversion products andcommingled catalyst is returned through line I I and valve It to theupper portion of chamber l0, thus setting up a local cycle of thismaterial within the reaction chamber.

The function of separating chamber H is to separate the conversionproducts supplied'thereto into a stream of relatively clean-vapors and-aresidual liquid fraction containing substantially all of the catalystparticles in the stream of conversion products supplied to this zone.The catalyst-containing residual liquid ispremoved from the lowerportion of chamber [4 through line 19 supply heat to .the reactants andconversion products passing therethrough.

The invention is not concerned with the speciflctype 0! catalystemployed for promoting the cracking reactionsolong as it is insuillciently and valve 20, preferably to suitable settling or filteringequipment, not illustrated, for separation of the catalyst particlesfrom the oil, fol-- lowing which the catalyst particles may bereactivated forfurther use in any --conventional manner, such as, forexample, by burning the deleterious" deposits therefrom in a-- stream ofoxygen-containinggases.

The vaporous conversion products from the upperportion of chamber llthrough line 2l and valve 22 to fractionator 23 from the upper portionof which. a fractionatedxvaporous stream of .the desired end-boilingpoint is re-.

moved. Higher boiling fractions of the vaporous conversion, productssupplied .tofractionator 23 are condensed in this.zoneas-refluxcondensate.

and, in the particular case here illustrated, the

total reflux condensate. so: formed is directed:

from the lower portion of. the fractionator through line 24 and-valve 28to pump 26. where-L from it'maybe supplied through line. 21 and valve 28to cooling and storage, or to thermal cracking treatment- .or elsewhere,as desired.

Preferably, however. all; a portion of the total,- or selected fractionsof the reflux condensate,- formed infractionator 23' are returned toheating are finely divided or powdered form to remain suspendedor'dispersed in the oil undergoing treatment and in the conversionproducts recycled to condenser 33 whereirom the resulting distillate anduncondens'ed. gases are directed through line 34 and valve 35 tocollection and separation in receiver 36. Uncondensed gases are releasedfrom the receiver through line 31 and valve 38 to storage or elsewhere,as desired, and distillate collected in the receiver is directedtherefrom through line 39 and valve 40 to storage or to any desiredfurther treatment.

When desired, regulated quantities of the distillate collected inreceiver '26- may bereturned therefrom by well known means, notillustrated, to the upper portion of fractionator 22 to serve as acooling and refluxing medium in this zone.

As a special feature of the invention, regulated quantities of thenormally gaseous conversion products collected in receiver 36 arereheated and returned to the reaction chamber. To accomplish thus, gasesare removed from receiver 36 through line II and supplied through valve42 in this, line to compressor 43 and thence fed through line 44 andvalve 45 to heater 46, wherein they are heated in any desired manner toor the reaction'zone; One such catalyst comprises .a-substantially.impalpable powder consisting es sentially of silica and one or moremetal oxides, such as alumina, zirconia, titanic. and thoria, the powderbeing obtained by precipitation of one or more of the active ingredientsfrom a solution. No novelty is claimed herein for this particularcatalyst nor for its method of preparation and, as previously mentioned,any known cracking catalyst capable of accomplishing the desired resultsmay be employed within the scope of the invention.

The amount of catalyst employed in relation to the quantity ofoiltreated will depend upon thenature of the oil, the specificcomposition and activity. of the catalyst and the fineness ofsubdivision .of the catalyst particles. When cracking parafiinicdistillates or gas-oil, for example, with the precipitatedsilica-alumina catalyst powder, from 0.25 to 10% or more, by weight, ofcatalyst, based on the oil subjected to cracking treatment, has beenfound to give good results and, due to the provisions for maintainingsubstantially uniform temperatures in the reaction chamber and forrecycling .catalyst and conversion products therethrough, smalleramounts of. catalytic material may be employed in the improved processherein provided as compared with conventional catalytic crackingoperations of this general type employing the same charging stock and.under otherwise similar conditions, except for those resulting from theuse of the features of the invention The temperature employed at theoutlet of the heating coil may range, for example, from 850 to 1050? R,depending upon the nature of the charging oil and catalyst employed.Temperatures of from 900 F., upward will ordinarily be utilized forrelatively light oils and when intermediate liquid conversion productsof the process (relflux condensate) are returned to the heating coi Atemperature substantially the same or somewhat lower than that employedat the outlet of the heating coil is preferably maintained in thereaction-chamber.

cooling being accomplished in any conventional manner,,not illustrated'Preferably, the heating coiland reaction chamber are operated at' asuperatmospheric pressure which may. range, for example. from 30 to 100pounds, or thereabouts, per square inch, and substantially the same orreduced pressure may be employed in the succeeding fractionating,condensing and collecting equipment.

As an example of one specific operation of the process, as it may beaccomplished in an apparatus such as illustrated and above described,the charging stock is a Pennsylvania gas-oil of approximately 35 A. P.I. gravity which is supplied to the heating coil, together with thetotal reflux condensate from the iractionator and a quantity of finelypowdered silica-alumina catalyst amounting to approximately 2% by weightof the combined feed (raw oil plus reflux condensate) the temperatureemployed at the outlet of the heating coil is approximately 980 F., anda substantially uniform temperature of approximately 950 F., ismaintained in the reaction chamber by the introduction thereto, atspaced points in this zone, of normally gaseous products of the processwhich are heated prior to their introduction into the reaction chamberto a temperature of approximately 1000" F. Conversion products andcatalyst are recycled through the reaction chamber at the rate ofapproximately twice the volume of this material supplied to theseparating chamber. A substantially uniform superatmospheric pressure ofapproximately 50 pounds per square inch is employed throughout thesystem.

In an operation such as above described, I may obtain per barrel ofgas-oil charging stock supplied to the system approximately 60% of 400F., end-point gasoline having an octane number of approximately 73 asdetermined by the motor method or approximately 83 as determined by theresearch method. The additional products of the process consistessentially of normally gaseous fractions and residual liquid.

I claim as my invention:

1. A process for the conversion of hydrocarbon oil, which comprisesheating a flowing stream of the oil to be cracked to a catalyticcracking temperature while maintaining a dispersion of finely dividedcatalyst particles in said stream, supplying the resulting heated oiland dispersed catalyst to one end of an elongated reaction zone,removing resulting conversion products and catalyst in commingled statefrom the opposite end of the reaction zone, returning a portion of theresulting conversion products and catalyst to the reaction zone,separating from the remain ing portion cracked vapors and a catalystcontaining residue, fractionating the vapors to form a refluxcondensate, subjecting the fractionated vapors to condensation to formdistillate and uncondenscd gases, recovering the distillate, andreheating and returning regulated quantities of said uncondensed gasesto the reaction zone at a temperature regulated to maintain an activecracking temperature therein.

2. A'process for the conversion of hydrocarbon oil,-which comprisesintroducing a continuous stream of said oil, heated to crackingtemperature, together with a finely divided catalyst to one end of anelongated reaction zone and therein efiecting cracking of the oil,withdrawing'a continuous stream of conversion products and catalyst fromthe opposite end of said reaction zone, returning a portion of the lastnamed stream to the reaction zone along with the first named stream andseparating cracked vapors and catalyst containing residue from theremaining portion.

3. A process for the conversion of hydrocarbon oil, which comprisesheating a flowing stream of said oil, having dispersed therein finelydivided catalyst particles, to a cracking temperature, introducing theresulting heated oil and dispersed catalyst as a continuous stream toone end of an elongated reaction zone and therein effecting cracking ofthe oil, withdrawing a continuous stream of conversion products andcatalyst from the opposite end of said reaction zone, returning aportion of the last named stream to the re action zone along with theheated oil, and separating cracked vapors and catalyst containingresidue from the remaining portion.

4. A process for the conversion of hydrocarbon oil, which comprisesheating a flowing stream of said oil, having dispersed therein finelydivid ed catalyst particles, to a cracking temperature, introducing theresulting heated oil and dispersed catalyst as a continuous stream toone end of an elongated reaction zone and therein ef fecting cracking ofthe oil, withdrawing a continuous stream'of conversion products andcatalyst from the opposite end of said reaction zone, returr'ng aportion of the last named stream to the reaction zone along with theheated oil, separating cracked vapors and catalyst containing residuefrom the remaining portion, fractionating said vapors to form refluxcondensate, recovering the fractionated vapors, and supplying saidreflux condensate to the heating step along with said hydrocarbon oil.

5. The process of claim 1 further characterized in that the reheatedgases are supplied to the reaction zone at spaced points intermediatethe ends thereof.

GUSTAV EGLOFF.

DISCLAIMER 2,282,855.Gustav Eglojf, Chicago Ill. CATALYTIC Gbnvsnsron OFHYDROCARBON Oms. Patent dated May 12, 1942. Disclaimer filed October 23,1943, by the assignee, Universal Oil Products Company. Hereby entersthis disclaimer to claims 2, 3, and 4 of said patent.

[Ofiieial Gazette November 23, 1943.]

